The invention relates to microelectro-mechanical actuator devices and the use of arrays of these devices to provide reconfigurable circuits.
A common method of tuning prototype microwave circuits, or even fine tuning production circuits, is to selectively add or subtract tuning elements from the circuit while monitoring the effect of such tuning on a network analyzer. In the case of a microstrip circuit, the addition or subtraction of conductor metal, which changes the size and shape of the microstrip line, will alter the impedance characteristics of that line.
The advantage of this technique is that compensation can be added to account for differences in "ideal" modeled matching networks and the "real world" realization of those networks. In fact, it is not necessary for a modeled matching network to exist. A component can be matched to the preceding and following stages working from "scratch" with no prior knowledge of the circuit matching requirements. These techniques add flexibility to circuit design by allowing microwave integrated circuits (MICs) to be modified quickly without the need of a complete fabrication cycle run.
Disadvantages of this technique are that it takes a skilled and patient operator to tune the circuit and secure the tuning elements so that the performance of the circuit remains constant over time. Positioning of tuning elements is quite tedious as errors in element positioning of a few thousandths of an inch will dramatically affect circuit performance, especially at higher frequencies. These problems also make repeatability a problem. It is very difficult to manually reproduce a certain arrangement of tuning elements.
Conventional microstrip circuits are fine tuned by hand to optimize performance with modeled impedance matching networks that are fabricated on the substrate along with "chicken dots" or "confetti" to which additional tuning elements can be attached, if necessary. In this case, gold mesh patterns are added to the circuit and attached with a thermo-compression bonder.
A means by which tuning elements can be modified quickly, easily, and repeatably would significantly impact microwave circuit design and implementation. Tuning elements which can be reconfigured remotely and on demand would open up a new area of dynamic circuit tuning.